REUSABLE VACUUM BAG AND METHOD OF MANUFACTURING SAME

Abstract: A reusable silicone vacuum bag (1) is manufactured by making a silicone vacuum bag envelope (1) having peripheral edges (2, 3, 4, 5). The bag envelope is spread so that the peripheral edges frame the envelope. Fluorinated ethylene propylene (FEP) is bonded to an area (6, 7, 8, 9) bordering the peripheral edges. The bag envelope is folded over on itself at the peripheral edges. Edge sealing tape (11) is applied to the FEP (10) in the area bordering the peripheral edges so that it covers the peripheral edges.

Description: REUSABLE VACUUM BAG AND METHOD OF MANUFACTURING SAME The present invention relates to a reusable vacuum bag and a method of manufacturing same. More particularly, the invention relates to a reusable silicone vacuum bag and a method of manufacturing same. Nylon bagging material is expensive, and a nylon bag can only be used once in an autoclave or oven cure. The nylon bagging material is highly susceptible to bridging, which could result in autoclave failure. Autoclave silicone vacuum bags are manufactured with silicone extruded edge seals, which are very expensive. These edge seals are attached to the appropriate tool. Furthermore, most silicone bags are stiffened on their periphery by a frame, which is cumbersome and creates a storage problem. The principal object of the invention is to provide silicone vacuum bags which may be reused. It is therefore an object of the present invention to provide silicone vacuum bags which may be reused. Another object of the present invention is to provide silicone vacuum bags which may be reused without causing autoclave failure. Another object of the invention is to provide silicone vacuum bags by a method which is not very expensive. Still another object of the invention is to provide silicone vacuum bags which are not cumbersome. Yet another object of the invention is to provide silicone vacuum bags which may be stored without difficulty. Another object of the invention is to provide compaction of composite plies which is not expensive. Still another object of the invention is to provide compaction of composite plies which is not cumbersome. Yet another object of the invention is to provide compaction of silicone composite plies which may be stored without difficulty. Another object of the invention is to provide a reusable silicone vacuum bag which is inexpensive in manufacture and efficient, effective and reliable in use and in storage. Still another object of the invention is to provide a method of manufacturing a silicone vacuum bag, which method has few and simple steps and is undertaken with facility and convenience by anyone ordinarily skilled in the art. Yet another object of the invention is to provide compacted composite plies and a method of compacting composite plies, which compacted plies and method of compacting are efficient, effective, reliable and inexpensive. Another object of the invention is to provide a silicone vacuum bag which eliminates "bridging," which occurs with nylon bags when used with a mold. In accordance with the invention, a method of manufacturing a reusable vacuum bag comprises the steps of making a vacuum bag envelope having peripheral edges, spreading the bag envelope so that the peripheral edges frame the envelope, bonding resin to an area bordering the peripheral edges, folding the bag envelope over on itself at the peripheral edges, and applying edge sealing tape to the resin in the area bordering the peripheral edges and covering the peripheral edges with the tape. The vacuum bag envelope is a silicone vacuum bag envelope. The resin comprises a film of fluorinated ethylene propylene (FEP) . In accordance with the invention, a method of manufacturing a reusable silicone vacuum bag comprises the steps of making a silicone vacuum bag envelope having peripheral edges, spreading the bag envelope so that the peripheral edges frame the envelope, bonding bondable FEP to an area bordering the peripheral edges, folding the bag envelope over on itself at the peripheral edges, and applying edge sealing tape to the FEP in the area bordering the peripheral edges and covering the peripheral edges with the tape. In accordance with the invention, a reusable vacuum bag comprises a vacuum bag envelope having peripheral edges. Resin and bondable FEP are bonded to an area bordering the peripheral edges and the envelope is folded over on itself at the peripheral edges. Edge sealing tape is applied to the FEP in the area bordering the peripheral edges and covers the peripheral edges. The vacuum bag envelope is a silicone vacuum bag envelope. In accordance with the invention, a method of compacting composite plies comprises the steps of making a silicone vacuum bag envelope having peripheral edges, spreading the bag envelope so that the peripheral edges frame the envelope, bonding bondable FEP to an area bordering the peripheral edges, folding the bag envelope over on itself at the peripheral edges, applying edge sealing tape to the FEP in the area bordering the peripheral edge, covering the peripheral edges with the tape and placing and compacting the composite plies in the silicone vacuum bag. In order that the invention may be readily carried into effect, it will now be described with reference to the accompanying drawings, wherein: FIG. 1 is a top plan view of an embodiment of the reusable silicone vacuum bag of the invention; FIG. 2 is a cross-sectional view, on an enlarged scale, taken along the lines II-II of FIG. 1; and FIG. 3 is a cross-sectional view, on an enlarged scale, of an embodiment of the apparatus for completing the method of the invention for compacting composite plies. Turning now in detail to the drawings, the reusabl silicone vacuum bag of the invention comprises a silicone vacuu bag envelope 1 (FIGS. 1 to 3) having peripheral edges 2, 3, 4 and 5 (FIG. 1) . In accordance with the invention, a bondable FEP is bonded to an area 6, 7, 8 and 9 (FIG. 1) which borders the peripheral edges 2, 3 , 4 and 5, respectively (FIG. 1) of the silicone sheets 1A and IB (FIGS. 2 and 3), which form the envelope 1. The FEP 10 (FIGS, l to 3) is fluorinated ethylene propylene-copolymers of tetrafluorethylene and hexafluoropropylene. The FEP is bondable. Edge sealing tape 11 of any suitable known type is applied between the two films or deposits of FEP 10A and 10B (FIGS. 2 and 3) in the area 6, 7, 8 and 9 bordering the peripheral edges 2, 3, 4 and 5, respectively, of the silicone sheets 1A and IB, and covers said peripheral edges. The method of the invention of manufacturing a reusable silicone vacuum bag comprises the steps of making the silicone vacuum bag envelope 1 (FIG. 1) having the peripheral edges 2, 3, 4 and 5 and spreading said bag envelope, as shown in FIG. 1, so that said peripheral edges frame or border said envelope. The next step of the method of the invention is to bond fluorinated ethylene propylene, or FEP 10, to an area bordering the peripheral edges 2, 3, 4 and 5, as shown in FIGS. 1 to 3. The bag envelope 1 is then folded over on itself, and, in accordance with the method of the invention, edge sealing tape 11 is applied between the two films of FEP 10A and 10B (FIGS. 2 and 3) in the area 6, 7, 8 and 9 bordering the peripheral edges 2, 3, 4 and 5, respectively, and covering said peripheral edges with said tape, as shown in FIGS. 2 and 3. The method of the invention of compacting composite plie comprises the steps of compacting composite plies such as, fo example, plies 12 and 13 (FIG. 3) in the silicone vacuum bag of th invention, as shown in FIG. 3. The silicone vacuum bag envelope 1 has vacuum ports 17 an 18 formed therein (FIG. 1) . When a vacuum is produced in the silicone vacuum bag envelope 1, said bag is ready for insertion in an autoclave. The methods of the invention may be applied to a tool by bonding the FEP to the borders of the bag envelope with the sealing tape applied between the bag and the tool. The sealing tape is then easily removed from the tool or the bag. This would no be true if the sealing tape were applied to the tool without the FEP. The method of the invention of compaction of composit plies is necessary in order to produce a reproducible component. Such method is faster and more efficient than methods which compac with nylon, PVC, or the like. While different embodiments of the present invention hav been shown and described, it is to be understood that many changes and modifications may be made thereunto without departing from the spirit and scope of the invention as defined in the appended claims.

Claims: WHAT IS CLAIMED IS: 1. A method of manufacturing a reusable vacuum bag, said method comprising the steps of making a vacuum bag envelope having peripheral edges; spreading said bag envelope so that said peripheral edges frame said envelope; bonding resin to an area bordering said peripheral edges; folding said bag envelope over on itself at said peripheral edges; and applying edge sealing tape to said resin in said area bordering said peripheral edges and covering said peripheral edges with said tape. 2. A method as claimed in claim 1, wherein said vacuum bag envelope is a silicone vacuum bag envelope. 3. A method as claimed in claim 2, wherein said resin comprises a film of FEP. 4. A method of manufacturing a reusable silicone vacuum bag, said method comprising the steps of making a silicone vacuum bag envelope having peripheral edges; spreading said bag envelope so that said peripheral edges frame said envelope; bonding bondable FEP to an area bordering said peripheral edges; folding said bag envelope over on itself at said peripheral edges; and applying edge sealing tape to said FEP in said area bordering said peripheral edges and covering said peripheral edges with said tape. 5. A method as claimed in claim 2, wherein said resin comprises a film of fluorinated ethylene propylene. 6. A reusable vacuum bag comprising a vacuum bag envelope having peripheral edges; resin and bondable FEP bonded to an area bordering said peripheral edges and said envelope being folded over on itself at said peripheral edges; and edge sealing tape applied to said FEP in said area bordering said peripheral edges and covering said peripheral edges. 7. A reusable vacuum bag as claimed in claim 6, wherein said vacuum bag envelope is a silicone vacuum bag envelope. 8. A reusable vacuum bag as claimed in claim 7, wherein said FEP is fluorinated ethylene propylene. 9. A method of compacting composite plies, said method comprising the steps of making a silicone vacuum bag envelope having peripheral edges; spreading said bag envelope so that said peripheral edges frame said envelope; bonding bondable FEP to an area bordering said peripheral edges; folding said bag envelope over on itself at said peripheral edges; applying edge sealing tape to said FEP in said area bordering said peripheral edges and covering said peripheral edges with said tape; and placing and compacting said composite plies in the silicone vacuum bag.

Inventors: CORNEAU LOUIS P JR, CORNEAU, LOUIS, P., JR.
Applicants: CORNEAU LOUIS P JR, GRUMMAN AEROSPACE CORP, CORNEAU, LOUIS, P., JR., GRUMMAN AEROSPACE CORPORATION
Application year: 1994
Main classification: B65D30
IPC codes: B29C43, B29C65, B31B1, B31B19, B65D30